Darcy's death has sparked more debate on the high number of malaria cases in the country this year.
The death toll for malaria in Burundi is rivalling the Ebola outbreak in neighbouring Democratic Republic of Congo, according to the WHO.
Malaria cases have reached epidemic proportions, the organisation said in a report that has been disputed by the Burundian government.
Health Minister Thaddée Ndikumana told journalists that the figures were lower - 4.3 million recorded cases, with 1,400 deaths this year.
He said this was a decrease since 2017, which saw 4.9 million malaria cases and 4,300 deaths.
The WHO recorded nearly 220 million cases of the illness in 2017, with an estimated 435,000 deaths worldwide. More than 90 per cent of malaria cases and deaths were in Africa.